Boiler.



' I PATENTED SEPT. 26, 1965.

IL,- MARCHESSAULTP BOILER. APPLICATION FILED JAN.3,1906.

2 SHEETS-SHEET 1.

' No. 800,226. PATENTBD SEPT. 26, 1905. L. MAROHBSSAULT.

BOILER. APPLICATION FILED I AN. 3\1905.

2 SHEETS-SHEET 2.

fly um 192 Aynnzw. a mum cm, rlwmu'maammms msnmavou. D. C.

- placed farther apart.

LOUIS MARCHESSAULT, OF MINNEAPOLIS, MINNESOTA.

' BOILER.

Specification of Letters Patent.

Patented Sept. 1905.

Application filed January 3, 1905. Serial No. 239,295.

To otZZ whom it may concern! Be it known that I, LOUIS MAROHESSAULT, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Boilers;

and I do hereby declare the following to be a 'full, clear, and exact description of the invention, such as will enable'others skilled in the art to which it appertains to make and use the same.

My invention relates to boilers, and has for its object to improve the same, as hereinafter set forth.

The invention consists of the novel devices and combinations of devices hereinafter described, and defined in the claims.

The invention is illustrated in the accompanying drawings, wherein like characters indicate 'like parts throughout the several vlews.

Figure 1 is a view in vertical section taken centrally through a boiler of the horizontal type, the same embodying the several features of my invention. Fig.2 is a horizontal section on the line 01: w of Fig. 1, some parts being broken away. Fig. 3 is an enlarged view,in horizontal section, taken on the line 00 m of Fig. 1, some parts being broken away; and Fig. 4 is a detall in elevation showing a portion of the flue-sheet of the fire-box and some of the flues.

The numeral 1 indicates the outer shell of a horizontal boiler of the usual construction,

and the numeral 2 indicates the shell of the fire-box. The flues 3 at one end open through the flue-sheet 2 of the fire-box and at their other end open through the front flue-sheet 1 into the usual smoke-box 4.

In order to secure the greatest possible amount of flue-surface exposed to the water, it has become the common practice to place the flues very close together, thereby leaving a very little area of metal in the flue-sheet between the fiues, and to compensate for this reduction in area it has been found necessary to use a much heavier flue-sheet than had hitherto been necessary when the flues were It is a well-known fact that the flue-sheet at thereceiving end of the fiues is subjected to a very intense heat and that great difliculty has been encountered, with the fiues closely spaced, to prevent rapid burning out of the flue-sheet and receiving ends of the flues and to prevent leaky joints between the flues and the flue-sheet due to excessive expansion of the sheet. It is obvious that the proper way to overcome the above defects is to provide for a freer circulation of water in the immediate vicinity of the joints between the fiues and the flue-sheet of the fire-box.

My invention accomplishes this result without reducing to any material extent the exposed radiating-surface of the fiues, and it consists in reducingthe ends of the flues adjacent to the flue-sheet of the fire-box substantially as shown in the drawings at 3. These reduced portions 3 should extend from the flue-sheet far enough to permit a materially-increased space between the flues, thereby permitting a much freer circulation of water. This construction accomplishes another important resultto wit, it leaves a greater area of metal in the flue-sheet between the fiues, and thereby permits the use of a much thinner flue-sheet than would be required in case the flues were left their full size from end to end.

In applying new flues to the boiler their ends should be reduced by swaging; but when old fiues are to be a plied their reduced ends may be formed by sl iort pipe-sections of smaller diameter than the body of the fiues, which sections should be telescoped into the flues and welded thereto. By this arrangement all of those advantages that are incident to the use of small fiues spaced far apart and which are incident to large flues closely spaced are attained and the objectionable features of both of such arrangements are I eliminated. Otherwise stated, by my im-' proved arrangement attain a maximum of ue radiating-surface and atthe same time leave suflicient area of metal in the fiuesheet to permit the use of comparatively thin flue-sheets.

The inside door-sheet of the fire-box immediately surrounding the door-o ening 5 is formed with an inward bulge 5, w hich is ap- IOO proximately semicircular in cross-section, and hence is free from angles in which sediment may lodge and which gives an increased space for water.

It is a known fact that the side sheets of the fire-box are subjected to the most intense heat at their lower central portions, and hence burn out at such points much more rapidly than at other points. This excessive heat also roduces excessive expan- 11o sion of the stay olts at such points. To overcome this, at least to a very great extent, I bulge inward the side sheets at their lower portions, as indicated in section in Fig. 2 and as indicated by the line marked a in Fig. 1, the said line 2 indicating the extreme upper portion of the said bulge. This gives a greatly-increased Water-space between the inside and outside sheets of the fire-box, Where the heat isthe greatest.

The boiler illustrated in the drawings is of the standard locomotive type of horizontal boiler; but it will be understood that my invention may be applied to other types of boilers.

What I claim, and desire to secure by Letlters Patent of the United States, is as foloWs:

1. In a boiler, a plurality of closely-assembled flues, said fiues having reduced ends Which reduced ends are extended through and in the vicinity of the Iluesl1eet of the fire-box, substantially as and for the purposes set forth.

2. In a boiler, the combination with an outer shell and a fire-box, said fire-box having a flue-sheet 2 spaced apart from an adjacent plate of the said outer shell, to form a mud-leg, of a plurality of fiues 3, having re duced ends 3 passed through said flue-sheet 2 and extending into the water-space a distance approximately equal to the thickness of said underlying mud-leg, substantially as described.

In testimony whereof I a-l'lix my signature in presence of two Witnesses.

LOUIS MARCHESSAUUI. Witnesses CHARLES MARonEssAUur, F. D. MEReIIAN'r. 

